Crank-case ventilation system for internal-combustion engines



Nov 6, 1928. 1,690,332

F. O. CLEMENTS CRANK CASE VENTILATION SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed May 11, 1925 2 Sheet-Sheet 1 .1/ a O l I 35 2Z4 4) Z4 Z zz 1 5 15;; Z/

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[K222255555 [HUEIZZUI Nov. 6, 1928. 1,690,332

F. o. CLEMENTS CRANK CASE VENTILATION SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed May 11, 1923 2 Sheets-Sheet 2 vaporized state due to the heat of the engine. Before air is circulated through the crank Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

FRANK O. CLEMENTS, OF DAYTON, OHIO, ASSIGNOR TO GENERAL MOTORS RESEARCH CORPORATION, OF DAYTON. OHIO, A CORPORATION OF DELAWARE.

CRANK-CASE VENTILATION SYSTEM.FOR INTERNAL-COMBUSTION ENGINES.

Application filed May 11, 1923. Serial No. 638,364.

This invention relates to the lubricating systems of internal combustion engines and has among its objects to eliminate from the lubricating oil relatively volatile diluents which tend to destroy the lubricating properties of the oil.

Another object is to prevent corrosion due to accumulation of combustion water in the oil and absorption thereby of the sulfur oxides, frequently present in combustion gases, with consequent formation of corrosive acids. v

Furtherobj eets and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown. I

The present invention provides apparatus for causing a current of air to pass through the crankcase of the engine and sweep out crankcase vapors which include matter such as water vapors and vapors of unburned fuel which have entered the crankcase from between the pistons and cylinders and are in a case, it passes through an air filter for removing foreign particles such as dust and grit which would be detrimental to the working parts of the engine housed by the crankcase.

In the drawings:

Fig. l is a plan view partly in section of a form of oil refining device including the present invention.

Fig. 2 is a front elevation of an internal 7 combustion engine partly in section and showing an air filter attached thereto.

Fig. 3 is a sectional view on line 33 of Fig. 2, and

Fig. 4 is a sectional view on line l4 of Fig. 1.

Referring to the drawings, the crankcase 20 of an internal combustion engine supports an oil pan 21 containin a quantity of lubri cant indicated by the level 22. The members 20 and 21 provide a housing for the crank shaftand connecting rods of the engine. The crankcase 20 supports a plurality of cylinders one of which is shown at 23 connected by a rod 24 with a crank shaft 25.

Each of the connecting rods 24 carries a finger 26 which dips into the oil 22 and causes it to be splashed within the crank shaft housing for lubricating the shaft and crank bearings and the cylinder walls.

During the operation of the engine relatively volatile substances, such as unburnt portions of the engine fuel and such as water of combustion may run down the cylinder walls and enter the crankcase. The fuel on condensing will dilute the lubricating oil and eventually ruin its lubricating qualities, while the water will absorb soluble gases from the combustion products which pass the pistons and form corrosive acids.

Heat from the engine will cause these relatively volatile substances to be vaporized and removed from the body of lubricating oil in the crankcase, or engine heat will tend to maintain the volatile matter in vaporized condition as it issues into the crankcase from between the pistons and cylinders. A mist including water vapor and engine fuel vapor will be present in the crankcase while the engine is running, and when the engine cools this mist will condense and pollute the lubrieating oil.

p The present invention includes means for removing' the crankcase vapors while the engine is in operat on so that when the engine cools there will be substantially no condensable matter present in the crankcase to pollute the lubricating oil. This means includes apparatus for causing air to circulate through the crankcase and to sweep out the crankcase vapors.

A dust separator 30 is supported by the engine frame in any suitable manner and'is provided with an air inlet 31 located in the path of air 'blowntoward the engine by. the cool ing fan 32 which is usually located back of communicates with the interior of a dust collecting receptacle 40. There is provided centrally of the separator body 38 an annular ledge 41 supporting the annular flange 42 of a sleeve 43 provided at its lower end with an inwardly extending flange 44. The flange 44 supports a flange ring 45 attached to the lower end of a conical tubular member or screen of fine mesh wire 46. The screen 46 is provided at the top with a cap 47 and its sides are provided with a sheathing of loosely packed fibrous material 48 such as loosely packed felt. The members 46 and 48 constitute an air filter which provides communication between the dust receptacle 40 and the chamber 49 from which a separator outlet passage 50 leads into the crank shaft housing at 51. A cap or cover 52 secured in any suitable manner as by screws 53 maintains the filter in position and closes the upper end of the chamber 49.

The crankcase 20 is provided with a vent or breather 60 which may be of any suitable type.

During the operation of the engine the fan 32 will blow air into the separator intake 31 causing it to pass with a swirling motion down into the dust chamber 40 as indicated by the arrows 54 in Fig. 3, and arrows 55 and 56 in Fig. 4. The heavier dust particles will be thrown outwardly against the wall of the receptacle 40 and will fall from the receptacle through an orifice 57. The air in the receptacle 40 will be forced throu h the filter 48beforc passing into the chamier 49 and substantially all of the finer dust particles will be removed. Relatively clean air passes into the crankcase through the passages 50 and 51 and mingles with the va ors in the crankcase, sweeping them out through the breather 60.

From the foregoing it is apparent that heat from the engine is used to refine the engine lubricating oil by vaporizing relatively volatile matter within the crankcase. Crankcase vapors are removed by using the engine cooling fan to cause air to pass through the crankcase and drive out these vapors, thereby minimizing the dilution of lubricating oil by condensation of crankcase vapors, and therefore tending to preserve the lubricating properties of the engine oil.

\Vhile the form of embodiment of the invention as described constitutes a preferred form it is to be understood thatother forms might be adopted, all coming within the scope of the claims which follow.

What I claim is as follows:

1. The combination of an internal combustion engine having a crankcase provided with an air inlet and an air outlet, means for introducing air into said crankcase air inlet under pressure comprising a conduit facing an air stream, means in said conduit for effecting a sharp change in direction in the air current to produce a separation of dust'par ticles therefrom by operation of inertia, said conduit being provided with a port for the discharge of dust thus separated thereby preventing their entrance into the crankcase, the clean air passing through the crankcase and discharging through said air outlet.

2. In the combination as defined in claim 1, a filter arranged between said last named means and the crankcase operating to separate particles of fine dust from the air current.

3. The combination of an internal combustion engine provided with the usual enine driven fan, and having a crankcase provided with an air inlet conduit at its forward end and adjacent the fan for receiving a portion of the air set in motion by the fan, means in said conduit for impressing a helical motion u on the air current passing therethroug for effecting the separation of dust particles from the current by centrifugal action, said conduit being provided with a port for the discharge of dust thus separated and an air discharge port at the rear of said crankcase the clean air passing through the crankcase removing diluent vapors therefrom and passing outwardly through said discharge port.

4. The combination of an internal combustion engine having the usual cooling fan and crank case, an air inlet for the crank case located at the rear of the fan and adjacent the outer periphery thereof, said air inlet being in the form of a tortuous passage and having a dust outlet intermediate its length, whereby particles of dust are separated by operation of inertia and discharged througi said dust outlet, an air outlet for said crankcase, the clean air traversing the crankcase and passing outwardly through said outlet.

In testimony whereof I hereto affix my signature.

FRANK O. CLEMENTS. 

